1. Field of the Invention
The present invention relates to external memory devices. More particularly, the present invention relates to an external memory device that provides disk device and optical device functionality.
2. Description of the Prior Art and Related Information
Today, computers are routinely used both at work and in the home. Further, with the advent of lap-tops and personal digital assistants, computers are being used while traveling and during many typical daily and nightly activities. Today, people use computers all the time.
Computers advantageously enable file sharing, the creation of electronic documents, the use of application specific hardware, the ability to play games, music and videos, and enable electronic commerce through the Internet and other computer networks. Most computing systems have a plurality of internal storage devices to aid in accomplishing these functions.
For example, with reference to FIG. 1, an example of a typical present day computer environment 100 with a host computer system 102 having a processor 104 (e.g. a central processing unit (CPU)) is shown. A typical host computer system 102 has a plurality of internal storage peripherals such as a hard disk drive (HDD) 103, a compact disk (CD) drive and/or digital video disk (DVD) drive 106, as well as a floppy drive 107. Also, typical host computer systems include a plurality of input/output (I/O) devices 106 such as display monitors, keyboards, speakers, etc.
Further, it has become increasingly common to utilize external disk drives that are easily removable from the host computer system 102 such that data can be readily transferred from one computer to another. For example, it is useful to have an external disk drive that can be used at work where work related projects are stored and that can then be easily removed and taken home. In this way, the removable external disk drive can then be plugged into a home computer so that an employee can work on work-related projects at home.
Many of these external disk drives utilize today's very prevalent Universal Serial Bus (USB) interface 110 to interface with external storage peripherals such as external disk drives. In fact, as shown in FIG. 1, often times a USB hub 130 is utilized to provide access to a plurality of storage peripherals. For example, in a common computer environment 100, a host computer system 102 may connect through a USB interface 110 to an external hard disk drive 120 being powered by an external power supply 122, and through a USB hub 130, may be connected to a plurality of other disk drives such as DVD disk drive 134, CD drive 138, and zip drive 142. All of these drives have their own respective external power supplies 136, 140, and 144, respectively.
Unfortunately, most external disk drives require external power sources such as power from a wall socket. This seriously inhibits mobility and the usefulness of the external drive. Further, battery-powered external disk drives have a very limited life-time before they need re-charging. Particularly, present day external CD drives, DVD drives, and larger HDDs typically require too much power to be powered by the host computer itself.
However, recently small mobile HDDs, often termed “thumb drives”, have been created that require far less power to operate and can be fully powered by a USB interface of the host computer system itself. Also, it should be noted that other types of memory devices, such as compact flash memory, can also now be fully powered by a USB interface. Unfortunately, optical disk drives, such as CD drives and DVD drives require a considerable amount of power to spin, read, and write to the optical media and, thus, cannot now (or most likely in the near future) be powered through an interface by a host computer system itself and require external power supplies.